In room V, the visitor can follow the progressive improvement of the telescope. The story begins with the first models developed by Galileo in 1610: on display are the only two remaining telescopes of the many made in his own workshop. These devices enabled the Pisan scientist to take a giant leap forward in astronomical research, making sensational discoveries in the process. Thanks to the new instrument, he observed that the Moon has valleys and mountains like the Earth, that the Milky Way is a gigantic cluster of stars, and that Jupiter is surrounded by four satellites or moons; later, he observed the strange appearance of Saturn, the phases of Venus, and sunspots. The telescope was transformed from a hand-crafted toy into an essential research instrument This evolution is documented in room V through Galileo's telescopes but also through those of Evangelista Torricelli, Eustachio Divini, and Giuseppe Campani. Another noteworthy item on view is the first binocular instrument, donated by its inventor Chérubin d'Orléans to Cosimo III de' Medici.